Astronauts take seven-hour spacewalk to fix cooling

Wednesday

Dec 25, 2013 at 12:01 AMDec 25, 2013 at 3:02 PM

CAPE CANAVERAL, Fla. - Two NASA astronauts spent more than seven hours working outside the International Space Station yesterday and repaired a critical cooling system. It was the second spacewalk in three days for flight engineers Rick Mastracchio and Mike Hopkins, who wrapped up the cumbersome work with only one problem. As they were installing a spare cooling pump, ammonia leaked out from one of four fluid lines. The toxic liquid turns to flakes in the cold and airless environment of space.

CAPE CANAVERAL, Fla. — Two NASA astronauts spent more than seven hours working outside the International Space Station yesterday and repaired a critical cooling system.

It was the second spacewalk in three days for flight engineers Rick Mastracchio and Mike Hopkins, who wrapped up the cumbersome work with only one problem.

As they were installing a spare cooling pump, ammonia leaked out from one of four fluid lines. The toxic liquid turns to flakes in the cold and airless environment of space.

The astronauts spent an extra 15 minutes in the station’s Quest airlock to bake out any residue on their spacesuits. The 71/2-hour spacewalk was broadcast live on NASA Television.

“It took a couple of licks to get her done, but we got it,” Hopkins radioed to flight controllers at NASA’s Mission Control Center in Houston.

An initial check in the final hour of the spacewalk showed the new pump was “alive and well,” NASA mission commentator Rob Navias reported.

During a spacewalk on Saturday, the astronauts removed a failed cooling system pump and attached it to a temporary storage site at the base of the station’s mobile rail cart.

NASA is considering a future spacewalk to repair the refrigerator-size pump and use it as a spare, officials said.

In addition to the new pump installed yesterday, there are two other spare pumps aboard the station, a $100 billion research complex that flies about 260 miles above Earth.

The U.S. side of the station, which includes Japanese and European laboratories, has been without half its cooling system since Dec. 11, when a valve failed inside a pump.

The six-member crew was never in danger, NASA said, but both cooling systems are needed to control heat from the station’s modules and labs.

With just one cooling loop, astronauts had to turn off unnecessary equipment and some science experiments. The Russian part of the station has a separate cooling system.

The spacewalks were NASA’s first since July, when the water-cooled spacesuit worn by Italian astronaut Luca Parmitano developed a leak.

Engineers then traced the problem to contaminated water in a device that circulates water and air in a spacesuit and takes moisture out of the air. How the water became contaminated remains unclear.